Manchester United has to win; their group is still up in the air. Real Madrid is almost guaranteed a through spot, but they still won't want to lose since it's not a mathematical certainty. PSG can punch their ticket today with just a draw, but there will still be jostling in Group C.

Bayern and Man City have already guaranteed their spots in Group D, so they may give their benches a run-out.

I'm pretty sure that stadiums at this level of play are required to have undersoil heating, so it's difficult for snow to accumulate on the pitch.Which is probably also why it looks a bit like a plowed potato field - the ground is wet and soft instead of frozen solid.